Lead isotopic compositions of Andean igneous rocks, latitudes 26 degrees to 29 degrees S; petrologic and metallogenic implications

Lead isotopic data are reported for 12 whole rock samples of Mesozoic to Quaternary plutonic and volcanic rocks from an intensely mineralized transect of the ensialic Central Andean orogen. In contrast to the initial Sr isotopic ratios and large ion lithophile element abundances of these rocks, the Pb isotope ratios show no trend either with decreasing age or with distance from the continental margin.The ratios 207 Pb/ 204 Pb and 208 Pb/ 204 Pb …